An adjustable 3D printed arm using M3 bolts and nuts, you will need two of each per hinge. Use a reasonably hard filament like PLA. Adjust the friction of the hinges with a screwdriver, hinge needs support. I recommend printing with an isotropic infill like gyroid for higher strength as rectilinear or cubic has breaking points. My settings were 10% gyroid. Print as many pieces as you like to make it as long as you want, start with at least 3 of both the arm and hinge. There is an adapter for alligator clips. I will probably add more "modules" later. You can use one of the bases or just glue it to a decently wide object instead.